fix(css): avoid clamping portal/modal widget width to DOM parent

[andycall]

Root cause: auto-width WidgetElements mounted into a portal/modal subtree could have their used width clamped by the DOM/style-tree parent (e.g. 36px), producing incorrect maxWidth constraints in the popup render tree.

Changes:

• Only clamp widget constraints by style-tree parent width when that parent renderer is an ancestor of the current render subtree
• Add integration_tests repro + custom elements for Cupertino modal popup portal width
• Add widget test guard for portal constraints

Test:

• integration_tests/specs/rendering/widget_portal_cupertino_modal_popup_width_not_clamped.ts

[vercel]

The latest updates on your projects. Learn more about Vercel for GitHub.

Project	Deployment	Actions	Updated (UTC)
use-case	Ready	Preview, Comment	Feb 2, 2026 6:33pm
vue_usecase	Ready	Preview, Comment	Feb 2, 2026 6:33pm